LT3932/LT3932-1
36V, 2A Synchronous
Step-Down LED Driver
FEATURES
DESCRIPTION
The LT®3932 , featuring the Silent Switcher®architecture
to minimize EMI/EMC emissions, utilizes fixed-frequency,
peak current control and provides PWM dimming for a
string of LEDs. The LED current is programmed by an
analog voltage or the duty cycle of pulses at the CTRL pin.
An output voltage limit can be set with a resistor divider
to the FB pin.
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±±1.5 LED ꢀCrrent ꢁegClatiꢂn
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±±125 ꢃCtꢄCt ꢅꢂltage ꢁegClatiꢂn
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.000:±/±0000+:± PWM Dimming at ±00Hz
(LT3932/LT3932-±)
±28:± Internal PWM Dimming
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Sꢄread-SꢄectrCm FreqCency MꢂdClatiꢂn
Silent Switcher® ArchitectCre fꢂr Lꢂw EMI
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3.6V to 36V Input Voltage Range
The switching frequency is programmable from 200kHz to
2MHz by an external resistor at the RT pin or by an exter-
nal clock at the SYNC/SPRD pin. With the optional spread
spectrum frequency modulation enabled, the frequency
varies from 100% to 125% to reduce EMI. The LT3932
also includes a driver for an external, high side PMOS for
PWM dimming and an internal PWM signal generator for
analog control of PWM dimming when an external signal is
not available. The LT3932-1 permits higher dimming ratios.
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0V to 36V LED String Voltage
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200kHz to 2MHz with SYNC Function
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99.9% Maximum Duty Cycle
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20:1 Analog or Duty Cycle LED Current Control
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Open/Short LED Protection and Fault Indication
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Accurate LED Current Sense with Monitor Output
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Programmable UVLO
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Thermally Enhanced 28-Pin (4mm × 5mm) QFN
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AEC-Q100 Qualified for Automotive Applications
Additional features include an LED current monitor, an
accurate EN/UVLO pin threshold, open-drain fault report-
ing for open-circuit and short-circuit load conditions, and
thermal shutdown.
APPLICATIONS
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Automotive Lighting
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Industrial and General Purpose Lighting
All registered trademarks and trademarks are the property of their respective owners. Protected
by U.S. Patents including 7199560, 7321203, 9596728, 9642200 and other patents pending.
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Machine Vision Systems
TYPICAL APPLICATION
2A LED Driver with Internal PWM Dimming
ꢀꢁꢂꢃ
CC
Internal PWM Dimming
ꢀ
ꢀꢁꢂ
ꢀꢁ
ꢀ
ꢀꢁꢂ
ꢀꢁ
ꢀꢁꢂꢃꢄ
ꢀꢀꢁꢂ
ꢀꢁꢂꢃ
ꢀꢁ
ꢀꢁꢂꢃꢄ
ꢀꢁꢂꢃꢄꢅꢆ
ꢀꢁꢂꢃ
ꢀ
ꢀꢁꢂ
ꢀꢁ
ꢀꢁꢂꢃꢄꢅꢂ
ꢀꢁꢂꢃꢄ
ꢀꢀꢁꢂ
C
ꢀꢁꢂ
ꢀꢁꢁꢂꢃ
ꢀꢁ
ꢀꢁꢂꢃꢂꢄ
ꢀꢁꢂꢃꢄ
ꢀꢁꢂꢃꢄꢅꢂ
ꢀꢁ ꢂꢁꢃ
ꢀꢁꢂ
ꢀ
Rꢀꢁ
ꢀꢁꢂ
ꢀꢁ
ꢀꢁꢁꢂ
CꢀRꢁ
ꢀꢁꢂ
ꢀꢁꢂꢃꢄꢅ
ꢀꢁꢀꢂꢃ
ꢀꢁꢁꢂ
ꢀꢁꢂ
ꢀꢁꢂꢃ
ꢀꢁꢂꢃꢄꢅ
50mΩ
ꢀꢁꢀꢂ ꢃꢄꢅꢆꢇ
ꢀꢁꢂꢃ
ꢀꢁꢂ
CC
ꢀꢁꢂꢃꢄꢅꢆ
ꢀꢁꢁꢂ
ꢀꢁꢂ ꢃ ꢄꢅꢆꢇꢈꢉ
ꢊꢈꢋ ꢀꢁꢂ ꢌꢍꢎꢏ Rꢐꢎꢑꢒꢓ
ꢀꢁꢂꢃꢄ
ꢀꢁꢀꢂꢃ
FAULT
FAULT
ꢀꢁꢂCꢃꢀꢄRꢅ
ꢀꢀ
ꢀꢁꢂꢃꢄ
ꢀꢁꢂꢃꢄ
Rꢀ Rꢀ
ꢀ
C
ꢀꢁ
ꢀꢁꢂꢃꢄ
ꢀꢁꢂꢃ
ꢀꢁꢂꢃꢄ
ꢀꢁꢂꢃꢄꢅ
ꢀꢁꢂꢃ
ꢀꢁꢂꢃ
ꢀꢁꢁꢂꢃ
ꢀꢁꢀꢂ ꢃꢄꢅꢆꢇ
Rev C
1
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